Effects of cis-platinum chemotherapy on otoacoustic emissions: The development of an objective screening protocol

To develop an objective, fast, and simply performed screening protocol for cis-platinum (CP) ototoxicity, we compared the efficacy of screening with distortion-product otoacoustic emissions (DPOAEs) with the outcome of both conventional and ultra-high-frequency (UHF) audiometry. Baseline audiometric and DPOAE testing was performed in 66 patients, 33 of whom met criteria for inclusion in the final database. Comparisons were made between baseline measurements and those recorded before subsequent CP infusions. Outcomes were analyzed clinically and with paired repeated-measures analysis of variance. Results indicated that DPOAEs and UHF were better measures than conventional audiometry. Further, DPOAEs may be better suited for screening older patients receiving CP chemotherapy because DPOAEs are as sensitive as UHF and are present in a greater number of these patients. Screening with DPOAEs may be enhanced by testing only in the 3- to 5.2-kHz range, thus decreasing testing time. Higher time averages to increase the signal-to-noise ratio and use of this narrower bandwidth might also allow for accurate bedside testing. (Otolaryngol Head Neck Surg 1999;121:693-701.)     

Neonatal hearing screening with otoscopy, auditory brain stem response, and otoacoustic emissions

A study was performed to investigate the relationship between external and middle ear factors and hearing screening results by auditory brain stem response (ABR) and transient evoked otoacoustic emissions (EOAEs). The ears of 200 well newborns aged 5 hours to 48 hours underwent screening by ABR and EOAEs, followed by otoscopic examination. The pass rates for ABR and EOAE screening were 88.5% and 79%, respectively. On otoscopic examination, 13% (53 of 400) ears had occluding vernix obscuring the view of the tympanic membrane. Cleaning of vernix was attempted in ears that failed ABR or EOAE screening. Seventeen ears that failed ABR were cleaned, and 12 (71%) of them passed repeat ABR. Thirty-three ears that failed EOAE screening were cleaned, and 22 (67%) of them passed repeat emissions testing. Cleaning vernix increased the pass rates for ABR and EOAE screening to 91.5% and 84%, respectively. Decreased tympanic membrane mobility was found in 9% of ears that could be evaluated otoscopically. Increased failure rates for both ABR and EOAE screening were found in infant ears with decreased tympanic membrane mobility, but significance testing could not be performed because of inadequate sample size. Prevalence of occluding external canal vernix and middle ear effusion as a function of increasing infant age were studied. Implications for newborn hearing screening are discussed. (Otolaryngol Head Neck Surg 1997;116:597-603.)     

Histopathology of human temporal bone after cis-platinum, radiation, or both

Preserving organs by use of multiple modalities has become protocol in treating squamous cell carcinomas of the head and neck, but cis-platinum and radiation can impair hearing. To determine the effect of cis-platinum, radiation, or a combination of these treatments on the temporal bone, we studied histopathologic slides of 15 human temporal bones: four after cis-platinum, five after radiation, two after combined treatment, and four from normal controls. Hair cells and cells in spiral ganglia were counted in reconstructed organs of Corti. Lumen-to-diameter indexes in arterioles near facial nerves were quantified for four normal controls and seven irradiated patients. Available audiograms were compared. Decreased spiral ganglion cells, loss of inner and outer hair cells, and atrophy of stria vascularis were demonstrated in groups receiving cis-platinum, radiation, and combinations, compared with age-matched controls. Arterioles around facial nerves demonstrated fibrinous clots within the intima, endothelial proliferation, and hypertrophy and fibrosis of vascular walls in smooth muscle. Fibrosis in connective tissue was clearly progressive after radiation. Cis-platinum and radiation can contribute to otologic sequelae, including sensorineural hearing losses, vascular changes, serous effusion, or fibrosis. Prophylactic treatments and techniques to deliver them should be considered for protection of temporal bones and preservation of hearing after oncologic modalities. (Otolaryngol Head Neck Surg 1998;118:825-32.)     

Differentiation of brain stem anesthesia from high spinal anesthesia using auditory brain stem response

A 67-year old woman having intractable chronic postherpetic neuralgia at the neck to forearm for two years was treated with subarachnoid block. Initially, bolus of 1% lidocaine 8 ml, with methylprednisolone acetate 20 mg was injected intrathecally at 6th cervical intervertebral space. The auditory brain stem response (ABR) during high spinal block with intact consciousness was not depressed in its wave height. ABR recorded showed prolongation of latency of 3 and 5 waves and prolongation of 1-3 phase to phase interval without prolongation of 3-5 phase to phase interval. Intrathecal nerve block was then performed with 1% lidocaine 15 ml and methylprednisolone acetate 20 mg, because she complained awareness and shocking sensation with controlled respiration during the first block. She assured that she felt nothing during the second block. The ABR recorded during the second block showed near complete suppression in its height of all waves and prolongation of all wave latencies. During recovery period, 1-3 and 3-5 phase to phase interval prolongation was recorded. One can differentiate brain stem anesthesia from other state that induces unconsciousness after block which is capable of inducing accidental brain stem anesthesia. These two blocks improved activity of daily living of the patient and severity of her pain decreased to 1/5 to 1/10.     

Hearing threshold shift measured by otoacoustic emissions after shooting noise exposure in soldiers using hearing protectors.

OBJECTIVE: The aim of the study was to assess the influence of short-term impulse noise to temporary threshold shift in soldiers using hearing protectors. STUDY DESIGN AND SETTING: The study included 80 subjects with correct tympanic membrane and thresholds measured by pure-tone audiometry less than 20 dB. There were two groups: 40 soldiers protected during shooting and 40 young males who didn't shoot. TEOAE were performed by ILO 292 Echoport Otodynamics device 3 to 5 minutes before shooting and 2 minutes and 1, 2, and 3 hours after shooting. RESULTS: Short-term exposure to impulse noise generated by five gunshots from the rifle kbk AKMS hasn't induced temporary threshold shift of hearing for chosen frequencies in soldiers using hearing protectors. Spectral analysis for chosen frequencies revealed that measurement reproducibility, stimuli level, and probe stability appeared to be comparable and repeatable. CONCLUSION: Our results show that the use of hearing protectors safeguarded against impulse noise. SIGNIFICANCE: The use of earmuffs is strongly recommended because they seem to sufficiently attenuate shooting noise.     

The brain stem function in patients with brain bladder--clinical evaluation using dynamic CT scan and auditory brainstem response

A syndrome of detrusor-sphincter dyssynergia (DSD) is occasionally found in patients with brain bladder. To evaluate the brain stem function in cases of brain bladder, urodynamic study, dynamic CT scan of the brain stem (DCT) and auditory brainstem response (ABR) were performed. The region of interest of DCT aimed at the posterolateral portion of the pons. The results were analysed in contrast with the presence of DSD in urodynamic study. DCT studies were performed in 13 cases with various brain disease and 5 control cases without neurological diseases. Abnormal patterns of the time-density curve consisted of low peak value, prolongation of filling time and low rapid washout ratio (low clearance ratio) of the contrast medium. Four of 6 cases with DSD showed at least one of the abnormal patterns of the time-density curve bilaterally. In 7 cases without DSD none showed bilateral abnormality of the curve and in 2 of 7 cases only unilateral abnormality was found. ABR was performed in 8 patients with brain diseases. The interpeak latency of the wave I-V (I-V IPL) was considered to be prolonged in 2 cases with DSD compared to that of 4 without DSD. In 2 cases with DSD who had normal DCT findings, measurement of the I-V IPL was impossible due to abnormal pattern of the ABR wave. Above mentioned results suggests the presence of functional disturbance at the posterolateral portion of the pons in cases of brain bladder with DSD.     

A quantitative assessment of the brain stem auditory evoked response during intraoperative monitoring

The brain stem auditory evoked response (BAER) was monitored intraoperatively in 11 patients with tumors of the posterior fossa. A technique for the objective quantitative assessment of the BAER based on the variance of the phase angle between small group averages is described. The resulting component synchrony measure corroborated standard peak latency and amplitude changes of the BAER during operative manipulation. A discussion of the replication and use of the objective measure is presented.     

Effects of intracochlear factors on spiral ganglion cells and auditory brain stem response after long-term electrical stimulation in deafened kittens.

Using an animal model, we have studied the response of the auditory brain stem to cochlear implantation and the effect of intracochlear factors on this response. Neonatally, pharmacologically deafened cats (100 to more than 180 days old) were implanted with a 4-electrode array in both cochleas. Then, the left cochlea of each cat was electrically stimulated for total periods of up to 1000 hours. After a terminal (14)C-2-deoxyglucose (2DG) experiment, the fraction of the right inferior colliculus with a significant accumulation of 2DG label was calculated. Using 3-dimensional computer-aided reconstruction, we examined the cochleas of these animals for spiral ganglion cell (SGC) survival and intracochlear factors such as electrode positions, degeneration of the organ of Corti, and the degree of fibrosis of the scala tympani. The distribution of each parameter was calculated along the organ of Corti from the basal end. There was a positive correlation between SGC survival and the level of fibrosis in the scala tympani, and a negative correlation between SGC survival and the degree of organ of Corti degeneration. Finally, there was a negative correlation between the 2DG-labeled inferior colliculus volume fraction and the degree of fibrosis, particularly in the 1-mm region nearest the pair of electrodes, and presumably in the basal turn.     

The fetal auditory brain stem response: serial measurements at two stimulus intensities

Eleven fetal lambs were tested for auditory brain stem responses (ABRs) at 105 and 90 db sound pressure level from 110 to 116 days until 133 days gestation. ABRs were elicited in response to 1200 clicks, presented at 16 clicks/sec, from a hearing aid receiver secured in the fetal external ear canal and recorded from subdermal stainless steel electrodes at the vertex (active electrode) and anterior pinna (reference electrode). Six term newborn lambs were tested similarly for ABR comparison. No fetal ABRs appeared before 117 days gestation. Thereafter, the ABRs exhibited decreasing peak latencies with increasing stimulus intensity and fetal age. Newborn ABR latency measurements were compared with predicted newborn values generated from linear regression analysis of fetal data. Newborn latencies to waves I and II approximated predicted values. Newborn latencies to waves III, IV, and V were much shorter than predicted, suggesting rapid maturation of higher brain stem and midbrain neurogenerators during late fetal development.     

Intraoperative auditory brain stem response monitoring during ultrasonic aspiration of posterior fossa tumors

The use of an ultrasonic aspirator may decrease the morbidity associated with the surgical removal of intracranial tumors by reducing the duration of surgery. In this study we monitored the auditory brain stem response (ABR) during ultrasonic surgical aspiration of 20 posterior fossa tumors. Twelve subjects had a transient decrement in the ABR during use of the ultrasonic aspirator; one had a temporary sensorineural hearing loss contralateral to the side of the surgery. Monitoring of the ABR during use of the ultrasonic aspirator in the posterior fossa helped minimize the risk of injury to normal structures. Changes in latency, amplitude, and interpeak interval of the ABR waves alert the surgeon to the need to adjust the aspirator settings or the conditions in the operative field before continuing to use the tool.     

Serial observations of brain stem function by auditory brain stem responses in central transtentorial herniation

Changes in auditory brain stem responses were serially investigated in a patient with downward transtentorial herniation due to acute obstructive hydrocephalus to correlate the neurological signs with the results of computerized tomography. Neurological deterioration correlated highly with disruption of auditory brain stem responses, especially with that of the components of waves V to VII. A noninvasive technique, the measurement of auditory brain stem responses is thought to be useful in detecting the severity of downward transtentorial herniation and in estimating the recovery of brain stem function after surgical treatment of intracranial hypertension.     

High-resolution CT scanning and auditory brain stem response in congenital aural atresia: patient selection and surgical correlation

Thirty patients with congenital aural atresia underwent CT scanning and/or auditory brain stem response (ABR) testing in a 20-month period. Eighteen patients had unilateral atresia and 12 had bilateral atresia. Twelve patients subsequently had surgery for repair of their atresia. CT scanning was not electively done until the patient was at least 2 years of age, while ABR testing was often performed in the first few months of life. Nineteen patients had CT scanning and 27 had ABR testing. The CT technique was found to offer specific advantages not previously observed in other methods of radiographic evaluation: (1) the course of the facial nerve was more easily traced and (2) the presence (or absence) of a stapes was more easily noted. The ABR was measured for monaural air-conduction as well as mastoid-placement bone conduction click stimuli; simultaneous multielectrode two- or four-channel recordings were employed. With this measuring technique it was not only possible to enhance wave I detection but, more important, the laterality of ABR wave I could be noted.     

Clinical study of intracranial pressure and auditory brain stem response in the cases of diffuse axonal injury]

The course of intracranial pressure (ICP) and the finding of auditory brain stem response (ABR) was discussed in the cases diagnosed as diffuse axonal injury (DAI) established by Gennarelli. ICP was measured in twenty-six cases which were divided into three groups according to the course of ICP: Group (1), in which ICP remained below 20 mmHg (group I, 9 cases). Group (2), in which ICP rose above 20 mmHg but was controlled by therapy (group II, 8 cases). Group (3), in which ICP rose above 20 mmHg and could not be controlled by any therapies (group III, 9 cases). Glasgow outcome scale 3 months after the injury in the cases of group I and II was severe disability (SD) and/or persistent vegetative state (PVS), but all of the cases in group III died. The findings of serial ABR were divided into 3 groups. These were group A (2 cases) which showed normal record, group B (5 cases) which showed elongation of latencies between the first and fifth waves, and group C (5 cases) in which there was no response in ABR. GOS in group A or B was SD and/or PVS, but all of the cases in group C were shown to be dead in GOS. Our studies suggest that the level of ICP in DAI is rather higher than that published in previous reports, and the continuous measurements of ICP and serial records of ABR are useful for evaluating the outcome of DAI.     

脑外伤后综合征患者脑电图和脑干听觉诱发电位异常分析

目的探讨脑外伤后综合征（PTBS）的脑电图（EEG）、脑干听觉诱发电位（BAEP）特点。方法对本院2005年9月至2010年10月门诊及住院就诊的659例患者诊断为PTBS行EEG和BAEP检查,并与662名健康志愿者的EEG、BAEP作对照分析。结果 PTBS病患EEG轻度异常533例（80.9%）,中度异常6例（0.9%）,重度异常0例（0%）。与正常组比,有显著差异（P〈0.01）。PTBS病患检测BAEP结果显示,BAEPI波潜伏期与对照组相比差异无显著意义（P〉0.05）。BAEP其他波潜伏期及峰间期均延长,与对照组有显著差异（P〈0.001）。EEG异常越重,BAEP异常率越高,BAEP异常也越明显。结论 EEG与BAEP联合应用,可以评估脑外伤患者的预后。     

Advantages of the retrosigmoid approach in auditory brain stem implantation

From April 1997 to December 1999, six patients (five men and one woman), ranging in age from 22 to 37 years with neurofibromatosis type 2 (NF2) were operated on via the classic retrosigmoid-transmental (RS-TM) approach for removal of a vestibular schwannoma (VS) (tumor size from 12 to 40 mm) and for auditory brain stem implantation (ABI). After tumor removal, the floor of the lateral recess of the fourth ventricle and the convolution of the dorsal cochlear nucleos were reached, and the ABI was inserted. More recently, an ABI was implanted via the retrosigmoid approach in a 4-year-old boy with a cochlear malformation (common cavity) associated with cochlear nerve aplasia. Electrically evoked auditory brain stem responses (EABRs) and neural response telemetry (NRT) were performed to verify the correct positioning of the inserted electrodes. No major complications related to ABI were observed. ABI has been activated to date in five of the NF2 patients. Auditory sensations with various numbers of electrodes were evoked in all patients. We consider the RS-TM approach the route of choice for ABI insertion in patients with NF2 and good hearing, offering a chance of hearing preservation, and in patients with complete cochlear ossification, severe head trauma and cochlear fracture, or nerve disruption, or a combination of these. A new indication for ABI implantation via the RS approach is presented by patients with bilateral cochlear nerve aplasia.     

Hemispheric asymmetry for auditory processing in the human auditory brain stem, thalamus, and cortex

We report evidence for a context- and not stimulus-dependent functional asymmetry in the left and right human auditory midbrain, thalamus, and cortex in response to monaural sounds. Neural activity elicited by left- and right-ear stimulation was measured simultaneously in the cochlear nuclei, inferior colliculi (ICs), medial geniculate bodies (MGBs), and auditory cortices (ACs) in 2 functional magnetic resonance imaging experiments. In experiment 1, pulsed noise was presented monaurally to either ear, or binaurally, simulating a moving sound source. In experiment 2, only monaural sounds were presented. The results show a modulation of the neural responses to monaural sounds by the presence of binaural sounds at a time scale of tens of seconds: In the absence of binaural stimulation, the left and right ICs, MGBs, and ACs responded stronger to stimulation of the contralateral ear. When blocks of binaural stimuli were interspersed in the sound sequence, the contralateral preference vanished in those structures in the right hemisphere. The resulting hemispheric asymmetry was similar to the asymmetry demonstrated for spatial sound processing. Taken together, the data demonstrate that functional asymmetries in auditory processing are modulated by context. The observed long time constant suggests that this effect results from a "top-down" mechanism.